1. Field of the Invention
The invention relates to a recording and/or reproducing apparatus, and particularly relates to a guide arrangement.
2. Description of the Related Art
Such a recording and/or reproducing apparatus (hereinafter briefly referred to as the apparatus) and such a guide arrangement are known, for example from the patent document WO 98/44499 A1. The known apparatus is a so-called data streamer intended and constructed for the storage of large amounts of data on a magnetic tape. For this purpose, the known apparatus has drive means with the aid of which a magnetic tape is driven with a comparatively high transport speed, as a result of which a more or less satisfactory air film is formed between the magnetic tape and the guide surfaces of two guide arrangements, i.e. two tape guide rollers. Said apparatus further has a multi-track magnetic head whose relative position, i.e. its height position, with respect to a magnetic tape is controllable with the aid of an actuator device, so as to enable a plurality of predefined mutually parallel tracks on the magnetic tape to be followed as exactly as possible and thus always enable a correct recording and reproduction to be achieved. In the known apparatus external influences on the magnetic tape, but also internal conditions in the magnetic tape, may result in the magnetic tape being subjected to forces which cause the magnetic tape to be deflected transversely to the transport direction of the magnetic tape, as a result of which at least one tape edge of the magnetic tape comes into contact with an end flange of at least one of the two tape guide rollers. This contact of a tape edge of the magnetic tape with an end flange, in its turn, leads to variations of comparatively high frequency in the height position of the magnetic tape, which height variations lie in a frequency range of approximately 500 Hz and even higher. However, these high frequency variations in the height position of the magnetic tape occur not only in the area of the tape guide rollers but also in the area of the multi-track magnetic head, which as already stated is movable in height with the aid of the actuator device in order to always guarantee a correct tracking. However, with the aid of the actuator device in the known apparatus the multi-track magnetic head is only capable of following those variations in the height position of the magnetic tape whose frequency is lower than the frequency of the variations in the height position of the magnetic tape which are caused by the magnetic tape coming into contact with an end flange. With the aid of the actuator device the magnetic head can follow only variations in the height position of the magnetic head which have a frequency of approximately 200 Hz but not the afore-mentioned variations having a frequency of at least 500 Hz. However, this means that as a result of an undesired but frequently inevitable contact of at least one of the tape edges of the magnetic tape with an end flange a correct tracking is no longer guaranteed and, consequently, a correct recording and reproduction is no longer guaranteed.
It is an object of the invention to preclude the afore-mentioned problems and to provide an improved recording and/or reproducing apparatus and an improved guide arrangement, which improved embodiments always ensure a correct recording and/or reproduction even when a tape edge of a magnetic tape comes into contact with an end flange of a guide arrangement.
To achieve this object, according to the invention, the characteristics features are provided in a recording and/or reproducing apparatus.
To achieve the object, according to the invention, the characteristics features are provided in a guide arrangement.
Owing to the provision of the characteristic features in accordance with the invention it is achieved by simple means that there is a direct mechanical contact between the at least one damping projection of the at least one guide arrangement and the record carrier tape guided by means of this guide arrangement, i.e. no air film is formed between the guide surface of the guide arrangement and the record carrier tape at this location, as a result of which in the area of the damping projection a friction effect is produced between the record carrier tape and the damping projection, by means of which a damping of axial relative movements of the record carrier tape with respect to the guide arrangement is achieved. This guarantees that excursions of the driven record carrier tape in an axial direction of a guide arrangement, which excursions are caused by external influences on the magnetic tape as well as by internal conditions in the magnetic tape, are damped to such an extent by the at least one damping projection of the guide arrangement that at least one tape edge of the record carrier tape does not or only to a greatly weakened extent come into contact with an end flange of the guide arrangement, as a result of which no or hardly any high frequency variations in the height position of the record carrier tape occur and, as a consequence, such high frequency variations occur neither at the location of the magnetic head and therefore always a correct recording and/or reproduction by means of the magnetic head is guaranteed.
In a recording and/or reproducing apparatus in accordance with the invention and in a guide arrangement in accordance with the invention the use of one damping projection is adequate. However, in practice it has been advantageous to provide two damping projections that are axially spaced apart a distance from one another. It is to be noted that an embodiment of the invention may alternatively have more than two damping projections, for example, three, four, or five of such damping projections according to need. The number of damping projections also depends on the axial dimension of a guide arrangement.
In a recording and/or reproducing apparatus in accordance with the invention the at least one damping projection may extend parallel to a plane which is inclined with respect to the guide axis of the guide arrangement. The at least one damping projection may then in itself by slightly undulate. However, in practice it is has been advantageous when a recording and/or reproducing apparatus in accordance with the invention and a guide arrangement in accordance with the invention utilizes a damping projection extending parallel to a plane that extends perpendicularly to the guide shaft of the guide arrangement. This arrangement has proved to be advantageous in view of a construction which is as simple as possible and in view of a production which is as simple as possible.
In a recording and/or reproducing apparatus in accordance with the invention and in a guide arrangement in accordance with the invention, the at least one damping projection may be rectangular or trapezoidal or substantially triangular with one rounded free corner in a radial cross-sectional view. However, it has been particularly advantageous when a recording and/or reproducing apparatus in accordance with the invention and a guide arrangement in accordance with the invention has a dome-shaped damping projection when view in a radial cross section. Such an embodiment has proved to be advantageous in view of a simple production but primarily in view of cooperation as gentle as possible with a record carrier tape.
In a recording and/or reproducing apparatus in accordance with the invention and in a guide arrangement in accordance with the invention it has been proved to be very advantageous when the height of the damping projection is based on the speed of the transport of record carrier and the curvature of the guide surface of the guide arrangement. These embodiments have proved to be advantageous in tests carried out during the development of a recording and/or reproducing apparatus in accordance with the invention and a guide arrangement in accordance with the invention.
In a recording and/or reproducing apparatus in accordance with the invention and a guide arrangement in accordance with the invention it has proved to be particularly advantageous when, in addition, the characteristic features are provided. Such an embodiment has the advantage that the tape guide roller provided as guide arrangement is moved along by a record carrier tape when this record carrier is driven, as a result of which hardly any relative movement in a circumferential direction occurs between the record carrier tape and the at least one damping projection of the tape guide roller, which provides a particularly high damping effect of the at least one damping projection on axial excursions of the record carrier tape.
However, it is emphasized that a guide arrangement in accordance with the invention may alternatively have a curved and, preferably, cylindrical guide surface, which may be supported so as to be stationary or rotatable with respect to its guide axis, which guide surface may have an end flange in the area of each of its two axial ends, which flange does not have a direct mechanical connection with the guide surface. This makes it possible, for example, to combine a rotatably supported cylindrical guide surface of a guide arrangement with stationary end flanges of this guide arrangement.
The above-mentioned as well as further aspects of the invention will become apparent from the embodiments described hereinafter by way of example and will be elucidated with reference to these examples.